This section is intended to provide a background or context to the disclosed embodiments. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple communication devices. Each terminal can communicate with one or more base stations through transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the communication device, and the reverse link (or uplink) refers to the communication link from the communication device to the base stations. This communication link can be established through a single-in-single-out, multiple-in-single-out, or a multiple-in-multiple-out (MIMO) system.
In order to take full advantage of services that are provided on other networks, as well as for performing operations such as load balancing within a given network, a communication device may need to release some or all of its current radio resources in order to acquire certain resources within the same or different network. For example, in an LTE system, a communication device may be released from a connected mode through a procedure called “connection release with redirection,” which directs the communication device to release its current radio resource control (RRC) connection and move to a target carrier to camp in idle mode. The target carrier may be part of the LTE system (e.g., if the network is attempting to keep its camping load balanced across frequencies) or part of a different radio access technology (RAT). Non-limiting examples of a RAT include Universal Mobile Telecommunications Systems (UMTS), Mobile Telesystems (MTS), Global Systems for Mobile communications (GSM), Single Carrier Radio Transmission Technologies (1xRTT), High Rate Packet Data (HRPD) and the like.
In a different scenario, redirection of a communication device to a new RAT may be triggered by a circuit switched (CS) fallback procedure that is initiated from the LTE network with either a handover or a cell change order. The CS Fallback allows subscribers to transition to a circuit network to receive voice and/or other services. The CS fallback procedure directs the communication device to move onto a target RAT in an attempt to obtain these services, and the serving cell is chosen based on cell selection towards the RAT and frequency specified in the triggering message. In these and other types of “redirection procedures,” the current network directs the communication device to seek services on another RAT and provides information to guide the communication device in its search for an appropriate serving cell on the target RAT.
When a communication device is unable to procure the appropriate resources in a redirection attempt, traditional failure handling procedures tend to bring the communication device back to the original serving network. However, in some cases, it might be more desirable if the communication device does not return to the original network. For example, a communication device may be directed from an original LTE system, which does not support VoIP, to a CS-capable RAT in order to obtain VoIP services. In such a case, a return to the original LTE network may trigger another redirect to a CS-capable RAT, followed by another return to the LTE network, causing a back-and-forth ping-pong action between the two networks that prevents the communication device from obtaining the required services. It is, therefore, advantageous to provide intelligent redirect procedures that facilitate the procurement of resources when the initial redirect attempt for acquiring the target resources fails.